Is a defendant required to have a certificate of probable cause to challenge a sentencing enhancement where the plea agreement does not specify a specific sentence?

Rather, defendant's plea agreement provided that the trial court could impose a sentence at or below the agreed-upon maximum. Therefore, a certificate of probable cause is not required for defendant to appeal the sentencing enhancement on the basis of a change in the law. (See People v. Kelly (2019) 32 Cal.App.5th 1013, 1016 ["a certificate of probable cause is not required to challenge the trial court's exercise of sentencing discretion where the plea agreement does not specify a particular sentence"].)